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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of The Korean Institute of Electrical Engineers
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The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 58, Issue 12 - Dec 2009
Volume 58, Issue 11 - Nov 2009
Volume 58, Issue 10 - Oct 2009
Volume 58, Issue 9 - Sep 2009
Volume 58, Issue 8 - Aug 2009
Volume 58, Issue 7 - Jul 2009
Volume 58, Issue 6 - Jun 2009
Volume 58, Issue 5 - May 2009
Volume 58, Issue 4 - Apr 2009
Volume 58, Issue 3 - Mar 2009
Volume 58, Issue 2 - Feb 2009
Volume 58, Issue 1 - Jan 2009
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Synthetically Optimal Tie Switches Selection Algorithm Considering Important Elements in Distribution Power System
Kim, June-Ho ; Lim, Hee-Taek ; Yu, Nam-Cheol ; Lim, Il-Hyung ; Choi, Myeon-Song ; Lee, Seung-Jae ; Ha, Bok-Nam ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2079~2088
The optimal operation in distribution system is to select tie switches considering important elements(Load balance, Loss minimization, Voltage drop, Restoration index..) in distribution system. Optimal Tie Switches Selection is very important in operation of distribution system because that is closely related with efficiency and reliability. In this paper, a new algorithm considering important elements is proposed to find optimal location of tie switches. In the case study, the proposed algorithm has been testified using real distribution network of KEPCO for verifying algorithm and complex network for applying future distribution network.
Analysis on the Protective Coordination on Neutral Line of Main Transformer in Power Distribution Substation with Superconducting Fault Current Limiter
Kim, Jin-Seok ; Lim, Sung-Hun ; Moon, Jong-Fil ; Kim, Jae-Chul ; Hyun, Ok-Bae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2089~2094
The fault current has increased due to growth of distributed generations for the large power demand in power distribution system. To solve some problem such as excess of the circuit breaker's cut-off ratings, the superconducting fault current limiter(SFCL) has been progressed. However, the operational characteristics of the relay is changed by SFCL. Therefore, the proper impedance for the SFCL should be selected to keep protective coordination with the SFCL when SFCL is introduced on the neutral line of main transformer in distribution system. In this paper, the proper normal conducting resistance was suggested to solve the problem in case of the protection coordination with SFCL.
Estimation of Fault Location on Transmission Lines using Current Phasor
Yeo, Sang-Min ; Kim, Chul-Hwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2095~2100
Since most of the Extra High Voltage (EHV) transmission lines are untransposed and multi-circuits, errors are occurred inevitably because of the unbalanced impedances of the lines and so on. Therefore, a distance relaying algorithm applicable to the untransposed multi-circuits transmission lines needs to be developed. The proposed algorithm of fault location estimation in the paper uses the fundamental phasor to reduce the effects of the harmonics. This algorithm also analyzes the second-order difference of the phasor to calculate the traveling times of waves generated by faults. The traveling time of the waves generated by faults is derived from the second-order difference of the phasor. Finally, the distance from the relaying point to the faults is estimated using the traveling times. To analyze the performance of the algorithm, a power system with the EHV untransposed double-circuit transmission lines are modeled and simulated under various fault conditions such as several fault types, fault locations, fault inception angles and fault resistances. The results of the simulations show that the proposed algorithm has the capability to estimate the fault locations quickly and accurately.
Calculation of Network Analysis and Fault Decision using Equality Constraint Condition with MATLAB
Yang, Min-Uk ; Kim, Kern-Joong ; Hwang, In-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2101~2106
The power system state estimation and prediction are very important for operation. Because that accidents of the Power system are the cause that many devices and etc are damaged. Currently, almost every power systems have 2nd,3rd back-upsystem for prevention of accident. But prevention of accident by miss-operation, due to operator or miss data, has not acounter plan. Because, we need to estimate the power system for correcting miss data and preventing miss operation by operator. We suggest algorithm for integrity of power system network data.
A Restoration Automation Algorithm on a Fault in Substation of SCADA-coordinated Distribution Automation System
Hong, Jun-Ho ; Lim, Il-Hyung ; Lee, Seung-Jae ; Kim, Tae-Wan ; Choi, Myeon-Song ; Ha, Bok-Nam ; Lee, Sung-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2107~2114
It is impossible to take the instant action in the distribution system When fault occures in a substation because operation of the substation and the distribution system are separated. However the power system automation has been studying about unity operation and co-operation between SCADA and DAS(Distribution Automation System). In this paper proposes a new algorithm of efficiency restoration using a outage load switching to a healthy MTR a fault occurrence at a MTR in united system between DAS and SCADA. In addtion, proposed algorithm includes a outage restoration method which keeps MTR optimal capacity with reorganization of distribution network in case it can not restore outage state loads caused by shortage of healthy MTR remain capacity. In case that proposed sequence still can not complete restoration, this paper suggests a efficiency outage restoration with objective function included priority in outage loads. In the case studies, the proposed algorithm have been verified in 2 MTR and 3 MTR substation
A Novel Reclosing Scheme in Distribution System using Carrier Signal
Ko, Yun-Tae ; Seo, Hun-Chul ; Rhee, Sang-Bong ; Kim, Chul-Hwan ; Kim, Jae-Chul ; Hyun, Ok-Bae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2115~2121
This paper proposes the new reclosing scheme considering the recovery time of SFCL in distribution systems which is based on variable dead time control. The main idea is that it uses the carrier signal to distinguish whether the fault is instantaneous or permanent after tripping the line by recloser. The system and SFCL is modeled by using Electromagnetic Transient Program(EMTP) and the validity of the reclosing scheme presented in this paper is analyzed according to the fault resistance, the recovery time of SFCL and the fault clearing time.
A Study on the Reliability of Superconducting Fault Current Limiter and Adjacent Distribution Equipments
Bae, In-Su ; Kim, Sung-Yul ; Kim, Jin-O ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2122~2127
This study presents the failure rate and repair rate of Superconducting Fault Current Limiter(SFCL) and adjacent distribution equipments. When the fault current penetrated SFCL, the supply of electric power to the customers can be partly continued. It is expected that SFCL makes to improve the reliability index of customers. Contrary to the expectations, the series connection between SFCL and distribution system could deteriorate the reliability index. To evaluate the reliability index in the distribution system including SFCL, the failure rate and repair rate of SFCL are required as well as that of distribution equipments. Also, the insertion of SFCL makes to change the failure rate and repair rate of adjacent equipments. This study proposes a method to calculate the failure rate and repair rate of a component combining SFCL and adjacent equipments.
The Research for a Structure of Current Limiter using a Phasic Similitude of Magnetic Circuit
Ji, Geun-Yang ; Min, Kyung-Il ; Lee, Su-Won ; Jang, Bong-Hwan ; Moon, Young-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2128~2135
In this paper, current limiter using a magnetic switching which is based on magnetic flux change in the case of fault is proposed. This current limiter consists of iron-core and three parts of coils. One is the primary coil connected to the power system. Another is the secondary coil wound to the opposite direction of the primary coil's winding. The other is the secondary of the secondary coil which is a movable copper plate winding and located below the secondary coil. In the normal state, the magnetic flux produced in the primary and secondary coils flows to the opposite directions each other and becomes to be canceled out. Therefore the voltages induced between the coils are zero. In the case of a fault, at the moment of a fault occurrence recognition, the switch connected to a secondary coil is opened and the secondary of the secondary coil is pulled out to the outside of the iron-core. Then, magnetic flux becomes to flow through the iron-core. Accordingly, the voltage is induced between the both ends of the primary coil and makes the current reduced. Therefore it is possible to cut off the circuit breaker easily with the proposed current limiter. This paper analyzes the current limiting effects and the detailed results are given.
Probabilistic Technique for Power System Transmission Planning Using Cross-Entropy Method
Lee, Jae-Hee ; Joo, Sung-Kwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2136~2141
Transmission planning is an important part of power system planning to meet an increasing demand for electricity. The objective of transmission expansion is to minimize operational and construction costs subject to system constraints. There is inherent uncertainty in transmission planning due to errors in forecasted demand and fuel costs. Therefore, transmission planning process is not reliable if the uncertainty is not taken into account. The paper presents a systematic method to find the optimal location and amount of transmission expansion using Cross-Entropy (CE) incorporating uncertainties about future power system conditions. Numerical results are presented to demonstrate the performance of the proposed method.
Studies of Switching Transients and Power Quality Improvement in Microgrid PCC Switch
Jyung, Tae-Young ; Baek, Young-Sik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2142~2148
A microgrid is defined as two or more distributed generation or storage assets configured in a networks and capable of operation in parallel or independently form a larger electric gird, while providing continuous power to one or more end users. And when microgrid are separated from grid oprating protection devices by faults of the grid side, microsources should charge electrical power needs of loads in microgrid and operate maintaining power quality. The magnitude of the switching transients will vary based on voltage phase difference between microgrid and grid, when the microgrid is resynchronized to grid. In this paper, when microgrid is resynchronized to grid, we analyzed the existing problems for reducing switching transients of SS(Static Switch).
A Study on Power Factor Control of Inverter-based DG System with Considering the Capacity of an Active Harmonic Filter and an Inverter
Kim, Young-Jin ; Hwang, Pyeong-Ik ; Moon, Seung-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2149~2154
Electric power quality in power transmission/distribution systems has considerably been deteriorated with the increase in the capacity of distributed generators (DGs). It is because inverters, connecting DGs to conventional power grids, tend to generate harmonic current and voltage. For harmonic mitigation, a large amount of research has been done on passive and active filters, which have been operating successfully in many countries. This paper, therefore, presents how to adopt the filters to an inverter-based DG, with considering a system consisting of both inverter-based DG and harmonic filters. In particular, this paper describes the simulation results using the PSCAD/EMTDC: firstly, the relationship between total harmonic distortion(THD) of current and output power of DG: secondly, the harmonic mitigation ability of passive and active filters. The system, furthermore, is obliged to satisfy the regulations made by Korean Electric Power Corporation(KEPCO). In the regulations, power factor should be maintained between 0.9 and 1 in a grid-connected mode. Thus, this paper suggests two methods for the system to control its power factor. First, the inverter of DG should control power factor rather than an active filter because it brings dramatic decrease in the capacity of the active filter. Second, DG should absorb reactive power only in the range of low output power in order to prevent useless capacity increase of the inverter. This method is expected to result in the variable power factor of the system according to its output power.
Heat Transfer Analysis of Coupled Electromagnetic-Thermal Field for Power Transformer
Ahn, Hyun-Mo ; Oh, Yeon-Ho ; Hahn, Sung-Chin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2155~2161
In this paper, we dealt with the electro-thermal coupling analysis for temperature prediction of power transformer. Heat transfer coefficient are calculated using Nusselt number in accordance with heat source generated from transformer windings and core materials. The calculated temperatures in power transformer were compared to those of measured ones and showed good agreement. This coupling method using heat transfer coefficient can be used at the design stage of power transformer efficiently.
Design and Development of Low-Cost Switched Reluctance Motor Drive System
Ha, Keun-Soo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2162~2167
A Low cost and variable speed brushless motor drive system with single switch per phase is presented. The motor drive is realized with a novel two-phase flux-reversal-free switched reluctance motor and a split AC two switch converter. The strategy of the controller and the converter for its realization are described. Comparisons between a split AC converter, asymmetric converter, split DC converter, single controllable switch converter, and N+1 converter are performed for its device rating, cost, switching losses and conduction losses, and converter efficiency. The split AC converter is analyzed and simulated to verify the characteristics of the converter circuitry and control feasibility and the simulation results are presented. The efficiency with various loads is numerically estimated and experimentally compared from viewpoint of subsystem and system in details. The focus of this paper is to compare the presented motor drive system to the asymmetric converter system throughout experiments and demonstrate single switch per phase converter having comparable efficiency as the asymmetric converter system.
A Study on the Distance Between the Track Circuits Using Identical Frequency in Railway Track Circuit System
Kim, Min-Seok ; Lee, Jong-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2168~2174
Electrical railway system consists of rolling stock, track, signal and streetcar line system. Track circuit system is a vital system due to checking the location of trains. Track circuits are divided by using frequency and isolated electrically. Currently, there is not a regulation for the distance between track circuits using identical frequency. In case of installing additional track circuits in large stations or marshalling yard, the problem which is that the signal is not exactly transmitted to the track circuit occurs due to the mutual interference. In other words, the track circuit properly is not operated on account of wrong induction current by the mutual inductance between track circuits. In this paper, we suggest the electrical model between track circuits and numerically calculate demanded parameters in electrical model. The distance between track circuits satisfying the mutual inductance which does not happen to the mutual interference phenomenon is presented about the distance of track circuit. It is proved by using Matlab and PSpice program as the amplitude of mutual induced current.
Operational Characteristic Analysis of DC Micro-grid with Detail Model of Distributed Generation
Lee, Ji-Heon ; Kwon, Gi-Hyun ; Han, Byung-Moon ; Cha, Han-Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2175~2184
This paper describes operational analysis results of the DC micro-grid using detailed model of distributed generation. Detailed model of wind power generation, photo-voltaic generation, fuel-cell generation was implemented with the user-defined model of PSCAD/EMTDC software that is coded with C-language. The operation analysis was carried out using PSCAD/EMTDC software, in which the power circuit is implemented by built-in model and the controller is modelled by user-defined model that is also coded with C-language. Various simulation results confirm that the DC micro-grid can operate without any problem in both the interconnected mode and the islanded mode. The operation analysis result confirms that the DC micro-grid make it feasible to provide power to the load stably. And it can be utilize to develop the actual system design and building.
Harmonic Impact Studies of Grid-Connected Wind Power and PV Generation Systems
Lee, Sang-Min ; Jung, Hyong-Mo ; Yu, Gwon-Jong ; Lee, Kang-Wan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2185~2191
Wind power and photovoltaic(PV) generation systems are the fastest growing sources of renewable energy. The nonlinear devices, such as power electronic converter or inverter, of wind power and PV generation systems are the source of harmonics in power systems. The harmonic-related problems can have significant detrimental effects in the power system, such as capacitor heating, data communication interference, rotating equipment heating, transformer heating, relay misoperation and switchgear failure. There is a greater need for harmonic analysis that can properly maintain the power quality. By measuring harmonics of existing wind power and PV generation systems as harmonics modeling, the studies were made to see the harmonic impact of grid-connected wind power and PV generation systems.
Development of a Novel Tracking for Efficiency Improvement of PV System with Sensor Method
Choi, Jung-Sik ; Ko, Jae-Sub ; Chung, Dong-Hwa ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2192~2199
This paper proposes a novel tracking algorithm for efficiency improvement of photovoltaic(PV) system using sensor method. PV system of sensor method is exactly impossible to track a sun position when insolation is low or rapidly changed by the clouds and fogs. Also, in this case, tracking device is occurred energy consumption by unnecessary operating. This statement of reason, real power of PV system is not increased than fixed PV system in specified location. Therefore, this paper proposes a novel tracking algorithm considered insolation for efficiency improvement of PV system using sensor method. And this paper analyzes the generation volume and proves the validity of proposed algorithm as compared with the conventional PV tracking system using sensor method.
A Novel Single Converter and Single Inverter (1Con-1Inv) Topology and Control Algorithm for Photovoltaic-Fuel Cell Hybrid System
Kim, Jong-Soo ; Choe, Gyu-Yeong ; Lee, Byoung-Kuk ; Won, Chung-Yuen ; Lee, Tae-Won ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2200~2208
This paper presents a novel single converter and single inverter (1Con-1Inv) topology for photovoltaic (PV)-fuel cell (FC) hybrid system and a new control scheme for the PV-FC hybrid system is then proposed. The new topology and the unique algorithm can minimize volume and production cost of the hybrid system. Moreover, system efficiency can improve due to reduction of losses of hardware components and other control factors are well regulated using just 1Con-1Inv with the help of the proposed control algorithm. The validity of proposed algorithm is verified both computer simulation using PSIM and Matlab/Simulink program and experimental with 700W of PV and 600W of FC system.
Fabrication and Current Transport Properties of
Coated Conductor by PLD Process
Kwon, O-Jong ; Ko, Rock-Kil ; Koo, Hyun ; Bae, Sung-Hwan ; Jung, Myung-Jin ; Oh, Sang-Soo ; Park, Chan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2209~2213
(REBCO) coated conductors(REBCO CCs) have been studied for electric power applications which require high current density wires. As long as the critical transition temperature(Tc) is concerned, REBCO CCs with large
ions have been expected to have better current transport properties than those with smaller
ions. For this reason, REBCO's with large
ions which include GdBCO, NdBCO and SmBCO have been mainly considered as the superconducting layer of CCs. On the other hand, REBCO's with smaller
ions are expected to have advantages in the fabrication process of CCs because of the lower melting temperature. But it has not yet been made clear which REBCO is the most suitable for the superconducting layer of CCs. In this study, we investigated the current transport properties of REBCO CCs with small
ion and advantages of using that in the CC fabrication process. Thin films of TmBCO, which has smaller
ion than most other
ions, were fabricated on buffered metal substrate as the superconducting layer of CC by PLD process. TmBCO CC shows critical current density (Jc (77 K, sf) =
) high enough to be utilized for application in electric power devices. Compared with previous experiments using the same PLD system, deposition temperature was approximately
lower than NdBCO thin films on buffered metal substrates.
A Study on the Improvement of the Interface Contact and the Prevention of the Charge Recombination by the Surface Treatment of Transparent Conductive Oxide in Dye-sensitized Solar Cell
Seo, Hyun-Woong ; Hong, Ji-Tae ; Son, Min-Kyu ; Kim, Jin-Kyoung ; Shin, In-Young ; Kim, Hee-Je ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2214~2218
Dye-sensitized solar cell (DSC) has been considered as a possible alternative to current silicon based p-n junction photovoltaic devices due to its advantages of high efficiency, simple fabrication process and low production cost. Numerous researches for high efficient DSC in the various fields are under way even now. Among them, the compact layer, which prevents the back electron transfer between transparent conductive oxides and the redox electrolyte, is fabricated by various methods such as a ZnO dip-coating,
dip-coating, and Ti sputtering. In this study, we tried to fabricate the
compact layer by the spin-coating method using aqueous
solution. The effect of the spin-coating method was checked as compared with conventional dip-coating method. As a result, DSC with a spin-coated compact layer had 33.4% and 6% better efficiency than standard DSC and DSC with a dip-coated compact layer.
A Touch-sensitive Display with Embedded Hydrogenated Amorphous-silicon Photodetector Arrays
Lee, Soo-Yeon ; Park, Hyun-Sang ; Han, Min-Koo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2219~2222
A new touch-sensitive hydrogenated amorphous silicon(a-Si:H) display with embedded optical sensor arrays is presented. The touch-sensitive panel operation was successfully demonstrated on a prototype of 16-in. active-matrix liquid crystal display (AMLCD). The proposed system provides the finger touched point without the real-time image processing of information of the captured images. Due to the simple architecture of the system, we expect the introduction of large-area touch-sensitive display panels.
A Study on the Characteristics of
thin Film in Dye-sensitized Solar Cells using Electrospray Method
Kim, Hee-Je ; Lee, Jeong-Gee ; Hong, Ji-Tae ; Kim, Ho-Sung ; Lee, Dong-Gil ; Hur, Kook-Sung ; An, Tae-Pung ; Jang, Jin-Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2223~2228
Dye sensitized solar cells(DSCs) have been very economical and easy method to convert solar energy to electricity. DSC can reach low costs in future outdoor power applications. However, to commercialize the DSC, there are still many shortages to overcome such a low efficiency in a large size DSC. In this study, DSCs were fabricated by an electrospray coating method for the
thin film. They were compared with DSCs prepared by conventional coating methods. We conducted an experiment to obtain the optimized parameters of voltage, flow rate, incident angle and distance in the electrospray method. After we fabricated
film using that way, we investigated the characteristics of DSC through I-V Curve, SEM and EIS. This novel method shows stable performance with an energy conversion efficiency of 3.44 % under 1 sun illumination (AM 1,
A Study on Space Charge Distribution of HDPE Mixed with EVA
Jung, Eui-Hwan ; Heo, Jun ; Yoon, Jae-Hun ; Lim, Kee-Joe ; Lee, Hyung-Kyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2229~2235
In this paper, each specimen blended at weight proportions of 80% HDPE to 20% EVA, 70% HDPE to 30% EVA, 60% HDPE to 40% EVA, and 50% HDPE to 50% EVA was manufactured respectively. The insulation performances of the proposed insulator were compared with conventional XLPE, main insulating material of CV cable on the basis of the investigation results of DC insulation performances. From the space charge density, electric field and potential profiles with raising DC voltage and time variation in HE82, distortion of electric field distribution was improved. As EVA mixed into the bulks acts as nucleation in crystallization process of HDPE, the size of spherulites became decreased and finally formed continuous network structure. Ultimately, it resulted from extinction of space charge in the interfacial region of spherulites.
Investigation on Optimum Plasma Production Condition of a Magnetic Neutral Loop Discharge System
Sung, Youl-Moon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2236~2241
In this study, the electron behavior was investigated numerically in order to obtain guidelines for design and operation of a new plasma source by a magnetic neutral loop discharge (NLD). The optimum plasma production was investigated by using a 3-dimensional simulation model which enables the electron behavior calculation from source region to downstream region. The results showed that the high-density plasma produced around the magnetic neutral loop (NL) is transferred from the NL region to the downstream region along magnetic force lines. Also the avaraged electron energy is increased with the normalized RF electric field (F), which can be used to characterize the plasma production efficiency of NLD system. Considering the relation between F and plasma production, in-depth plasma control can be achieved at a given specific process condition.
Homogeneous Dual Composite Right/Left-Handed Metamaterial Using Subwavelength Defected Ground Structure(DGS)
Park, Woo-Young ; Lim, Sung-Joon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2242~2246
In this paper, a homogeneous dual composite right/left-handed (D-CRLH) transmission line (TL) is proposed by using a defected ground structure (DGS) on the ground plane. In order to satisfy a homogeneity condition of metamaterial, a subwavelength unit cell is designed by way of a spiral DGS and a meander stub. From a dispersion diagram, it is expected that the frequency bands for the left-handed (LH) property is 3.5 - 4.4 GHz. At 3.8 GHz in the LH band, backward propagating phenomenon is observed from full-wave analysis. The experimental results show that the proposed TL has a stop-band in 1.75 - 3.6 GHz.
Feed-through Noise Reduction Technique for MEMS Gyroscope
Park, Kyung-Jin ; Kang, Seong-Mook ; Baek, Chang-Wook ; Kim, Ho-Seong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2247~2252
Since the dimensions of MEMS gyroscope are very small compared to those of conventional gyroscope, MEMS gyroscope should be able to measure charge of pico-coulomb caused by very small change of electrodes gap. However, feed-through signal from driving electrodes to the sensing electrodes due to the electromagnetic coupling is much greater than the sensing signal, which degrades the sensitivity of MEMS gyroscope. This paper introduces the feed-through noise canceling technique using dummy port and confirms the feasibility of feed-through noise canceling experimentally. Experimental results shows that, when driving signal is 6 Vpp, 30 kHz, feed-through signal of vacuum packaged Si Gyroscope decreases from -53.2 dBm to -77.1 dBm by using feed-through reduction technique. Q-factor that could not be measured without noise reduction is measured to be about 2500 and resonance frequency to be 7.018 kHz.
Design and Implementation of Network Management System for BACnet
Park, Tae-Jin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2253~2260
BACnet is an international standard communication protocol especially designed for building automation and control systems. In this paper, a reference model of network management system for BACnet is proposed and its implementation method is introduced. In order to evaluate the feasibility and validity of proposed network management system, it is applied to a real experimental model of BACnet network system. Proposed network management system complies with standard BACnet protocol and its functions are implemented in software without hardware dependencies so that it can be applied not only to newly installed BACnet system but also to already installed BACnet system by software upgrade. The network management system and its implementation method introduced in this paper will help BACnet-based automation system to be managed efficiently and they can be practically applied in real BACnet-based automation systems.
New Delay-dependent Stability Criteria for Uncertain Stochastic Systems with Time-varying Delays
Kwon, Oh-Min ; Park, Ju-Hyun ; Lee, Sang-Moon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2261~2265
In this paper, the problem of delay-dependent stability of uncertain stochastic systems with time-varying delay is considered. The uncertainties are assumed to be norm-bounded. Based on the Lyapunov stability theory, new delay-dependent stability criteria for the system are derived in terms of LMI(linear matrix inequality). Two numerical examples are given to show the effectiveness of proposed method.
Velocity Estimation of a Compass Gait Biped Robot by Using Impact Condition and Initial Condition Reset
Son, Young-Ik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2266~2268
In this paper, a simple method of angle velocity estimation is presented for a passive dynamic biped robot. The estimation problem is not an easy task because its dynamic model is a hybrid system involved with an impact condition. Instead of designing a complex observer for hybrid systems we simply utilize the impact condition to reset the initial condition of the high-pass filter when the non-support leg hits the slope. The approach has been verified by simulation results.
Customer Clustering Method Using Repeated Small-sized Clustering to improve the Classifying Ability of Typical Daily Load Profile
Kim, Young-Il ; Song, Jae-Ju ; Oh, Do-Eun ; Jung, Nam-Joon ; Yang, Il-Kwon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2269~2274
Customer clustering method is used to make a TDLP (typical daily load profile) to estimate the quater hourly load profile of non-AMR (Automatic Meter Reading) customer. In this paper, repeated small-sized clustering method is supposed to improve the classifying ability of TDLP. K-means algorithm is well-known clustering technology of data mining. To reduce the local maxima of k-means algorithm, proposed method clusters average load profiles to small-sized clusters and selects the highest error rated cluster and clusters this to small-sized clusters repeatedly to minimize the local maxima.
Exercise Recognition using Accelerometer Based Body-Attached Platform
Kim, Joo-Hyung ; Lee, Jeong-Eom ; Park, Yong-Chan ; Kim, Dae-Hwan ; Park, Gwi-Tae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2275~2280
u-Healthcare service is one of attractive applications in ubiquitous environment. In this paper, we propose a method to recognize exercises using a new accelerometer based body-attached platform for supporting u-Healthcare service. The platform consists of a device for measuring accelerometer data and a device for receiving the data. The former measures a user's motion data using a 3-axis accelerometer. The latter transmits the accelerometer data to a computer for recognizing the user's exercise. The algorithm for exercise recognition classifies the type of exercise using principle components analysis(PCA) from the accelerometer data transformed by discrete fourier transform(DFT), and estimates the repetition count of the recognized exercise using a peak detection algorithm. We evaluate the performance of the algorithm from the accuracy of the recognition of exercise type and the error rate of the estimation of repetition count. In our experimental result, the algorithm shows the accuracy about 98%.
Development of Low Power PLC Modem for Monitoring of Power Consumption and Breaking of Abnormal Power
Yoon, Jae-Shik ; Wee, Jung-Chul ; Park, Chung-Ha ; Song, Yong-Jae ; Kim, Jae-Heon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2281~2285
Powerline communication is the data signal which is modulated by carrier frequency through the installed powerline at in-home or office is transmitted and received signals are separated into data signal with using band-pass filter which cent-frequency is carrier frequency. The home gateway, an equipment which works as an gateway for ubiquitous home network, relays all functions of a home network. The home gateway must always be connected in order to provide seamless services. However it gives unfavorable power consumption. Therefore the needs for working in maximum power saving mode while there is no data traffic and for invoking to the normal function when it is necessary. So, in this paper we survey the development of low power PLC modem monitoring of power consumption and breaking abnormal power in the home Network.
Sidelobe Suppression Technique in OFDM System Based on Phase Optimization of Subcarriers
Hwang, Hu-Mor ; Noreen, Shama ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2286~2291
We propose a phase optimization technique for sidelobe suppression in OFDM system. The technique is based on idea that phase shift to some of the transmit symbols within the symbol constellation plane can lead to significant sidelobe suppression. The sidelobes are reduced by optimizing using iterative method the phases of some subcarriers on the left and right hand side of the used OFDM spectrum. The proposed technique requires a small amount of side information that needs to be transmitted. Simulation results show that the proposed technique can reduce the sidelobes by significant amount.
Lossy Image Compression Based on Quad Tree Algorithm and Geometrical Wavelets
Chu, Hyung-Suk ; An, Chong-Koo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2292~2298
In this paper, the lossy image compression algorithm using the quad tree and the bandlets is proposed. The proposed algorithm transforms input images by the discrete wavelet transform (DWT) and represents the geometrical structures of high frequency bands using the bandlets with a 8 block- size. In addition, the proposed algorithm searches the position information of the significant coefficients by using the quad tree algorithm and computes the magnitude and the sign information of the significant coefficients by using the Embedded Image Coding using Zerotrees of Wavelet Coefficients (EZW) algorithm. The compression result by using the quad tree algorithm improves the PSNR performance of high frequency images up to 1 dB, compared to that of JPEG-2000 algorithm and that of S+P algorithm. The PSNR performance by using DWT and bandlets improves up to 7.5dB, compared to that by using only DWT.
Stable Active Noise Control Using Auto-Secondary Path Estimation Techniques
Nam, Hyun-Do ; Seo, Sung-Dae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 11, 2009, Pages 2299~2301
The adaptive IIR filters for active noise control systems are more effective when acoustic feedback exists, but the adaptive IIR filters could be unstable when the filter algorithm is not yet converged. In this paper, auto-secondary path estimation techniques and a stabilizing process for adaptive Multi-Channel Recursive LMS (MCRLMS) filters are developed to improve the stability of multi-channel active noise control systems. Experiments using a TMS320VC33 digital signal processor in a three dimensional enclosure have performed to show the effectiveness of the proposed algorithm.